• Abundance, composition and distribution of predatory gelatinous zooplankton in the northern Gulf of Alaska

      Mendoza Islas, Heidi M.; Hopcroft, Russell R.; Coyle, Kenneth O.; Cieciel, Kristin; Danielson, Seth (2020-08)
      Jellyfish are conspicuous yet under-studied components of marine zooplankton communities. Abundance, biomass, size, and distribution of large-jellyfish were measured during July and September of 2018 and 2019 as part of the Northern Gulf of Alaska Long-Term Ecological Research (NGA-LTER) cruises. Nearly 1000 kg dispersed among ~13,800 jellies were collected using a 5 m² Methot net. Catches were dominated by two macro-jellies, the hydrozoan Aequorea sp. and the scyphozoan Chrysaora sp. During 2018, epipelagic macro-jellies biomass averaged 1.46 ± 0.36 g WW m⁻³ for July and 1.14 ± 0.23 g WW m⁻³ for September, while during 2019 they averaged 0.86 ± 0.19 g WW m⁻³ for July and 0.72 ± 0.21 g WW m⁻³ by September. Despite similar biomass among sampling seasons within the same year, July abundances were fivefold greater than abundances in September, with July catches dominated by juvenile jellyfish over the inner shelf, while during September jellyfish adults were more prominent and most predominant at offshore stations. Comparison to over 20 years of data from standard towed nets allowed determination of the relative magnitude of the three dominant predatory zooplankton components: Scyphozoans, Hydrozoans, and Chaetognaths in the NGA. The biomass of these smaller epipelagic predators (10 mg WW m⁻³ for hydrozoans and 8 mg WW m⁻³ for chaetognaths) is a low percentage of the macro-jellies, despite their much higher numerical abundance. Acknowledging that changes in gelatinous biomass could have profound effects on fisheries, we argue that jellyfish should be quantitatively monitored in ecosystems with high fisheries productivity.
    • Addressing a complex resource conflict: humans, sea otters, and shellfish in Southeast Alaska

      Ibarra, Sonia Natalie; Eckert, Ginny L.; Monteith, Daniel; Pyare, Sanjay; Langdon, Stephen J.; VanBlaricom, Glenn (2021-05)
      Complex resource conflicts may benefit from the inclusion of social-ecological systems approaches that recognize the complex linkages between humans and their environment. Competition for shared shellfish resources by sea otters and humans in Southeast Alaska has caused food security concerns, cultural and economic losses, and uncertainty about the future of various fisheries, including rural subsistence-based fisheries. In rural Alaska Native communities, access to subsistence resources are critical to maintaining a way of life, with deeply rooted knowledge systems that are tied to the land, water, and natural resources. This dissertation documents Indigenous and local knowledge of Alaska Native customary and traditional food experts, sea otter hunters, and elders (hereafter harvest experts) to understand empirical observation and interpretations of restoring balance with sea otters. This work took place within the traditional territories of the Tlingit and Haida people of Southeast Alaska in four rural communities, Kake, Klawock, Craig, and Hydaburg. With Tribal leaders and harvest experts, my collaborators and I used a participatory framework that became a formal partnership to co-develop study goals, objectives, and methodology. Through a multiple evidence-based approach, I co-conducted semidirected and site visit interviews, structured questionnaires, mapping exercises, and participant observation in all four communities, and intertidal bivalve (shellfish) surveys in Hydaburg and Kake. Qualitative and quantitative approaches revealed local and Indigenous knowledge about sea otters caused changes to subsistence shellfish resources and harvesting patterns that included declines in availability and spatial extent of shellfish harvests, and shifts in shellfish harvest hotspots. Community adaptive strategies to observed shellfish declines include shifting harvest locations away from sea otter presence. Community management recommendations about restoring balance with sea otters include increasing sea otter hunting locally using spatially explicit techniques. Financial subsidies for sea otter hunters, creating local tanneries, legal changes to the Marine Mammal Protection Act, and market creation and development for sea otter handicrafts were noted as solutions to barriers of local implementation to management recommendations. Commercial and charter fisheries are other factors that have contributed to shellfish declines. Butter clam (Saxidomus gigantea) size and density declined with increased distance to community and increased sea otter activity near Hydaburg, demonstrating the influence of sea otters and human harvests on bivalve population dynamics. Application of these results about Indigenous knowledge, management, and governance systems to sea otter management in Alaska could create a more inclusive, equitable and community-driven management approach.
    • Advancing wildfire fuel mapping and burn severity assessment in Alaskan boreal forest using multi-sensor remote sensing

      Smith, Christopher William; Panda, Santosh; Bhatt, Uma; Meyer, Franz (2021-05)
      Wildfires in Alaska have been increasing in frequency, size, and intensity putting a strain on communities across the state, especially remote communities lacking firefighting infrastructure to address large scale fire events. Advances in remote sensing techniques and data provide an opportunity to generate high quality map products that can better inform fire managers to allocate resources to areas of most risk and inform scientists how to predict and understand fire behavior. The overarching goal of this thesis is therefore to build insight into methods that can be applied to create highly detailed fire statistic map products in Alaska. To address this overarching goal we tested several methods for generating fire fuel, burn severity, and wildfire hazard maps that were validated using data collected in the field. Applying the Random Forest classifier on Airborne Visible/ Infrared Imaging Spectrometer Next-Generation (AVIRIS-NG) hyperspectral data we were able to produce a fire fuel map with an 81% accuracy. We then tested two supervised machine learning classifiers, post fire standard spectral indices, and differenced spectral indices for their performance in assessing burn severity. We found that supervised machine learning classifiers outperform other algorithms when there is an adequate amount of training data. Using the support vector machine and random forest classifiers we were able to generate burn severity maps with 83% accuracy at the 2019 Shovel Creek Fire. Lastly, we looked for a relationship between burn severity and environmental conditions prevalent during the Shovel Creek and Nugget Creek fires. Overall, these products can be used by fire managers and scientists to assess fire risk, limit the damages caused by wildfires through adequate resource allocation, and provide the guidelines for creating future high quality fire fuel maps.
    • Age, growth, and movement dynamics of Arctic cod (Boreogadus saida) in the Chukchi and Beaufort seas

      Frothingham, Alyssa; Norcross, Brenda L.; Seitz, Andrew C.; Brown, Randy J. (2020-08)
      Arctic Cod (Boreogadus saida) dominates fish assemblages in the Arctic and provides a valuable food source to upper trophic level predators. Little is known about several important facets of its biology and ecology in the Pacific Arctic, including in the Chukchi and Beaufort seas. The physical connectivity of these two biologically and hydrologically unique seas provides an excellent opportunity to explore differences in Arctic Cod life history characteristics such as age, growth, and movement dynamics in these two adjacent areas. To establish a current benchmark of Arctic Cod life history and movement characteristics for the Pacific Arctic, Arctic Cod otoliths collected from 2009 to 2014 during twelve research cruises conducted throughout the Chukchi and Beaufort seas were used to estimate growth and age structure for this species from the two regions. Ages of Arctic Cod ranged from 0 to 5 years with significant overlap in size at age. Growth of Arctic Cod collected in the southern Chukchi Sea and eastern Beaufort Sea regions were similar, suggesting freshwater-influenced regions may enhance growth compared to other areas. Additionally, microchemistry of age-0 Arctic Cod otoliths was analyzed to determine potential differences in elemental signatures between the Chukchi and Beaufort seas, and to infer movement between them. Otolith trace element concentrations were distinct between the Chukchi and Beaufort seas, indicating populations of Arctic Cod from the Chukchi and Beaufort seas can be differentiated based on otolith elemental signatures. Furthermore, elemental signatures from the cores of otoliths were significantly different from those from the edges in both seas suggesting early life history movement. As the Pacific Arctic faces warming sea temperatures and sea ice reduction, predicting a species-level adaptation to a changing environment is nearly impossible without establishing a benchmark for future comparison. This research will provide valuable insight into Arctic Cod across a broad portion of its distribution.
    • Alaska Native men's voices: tracking masculinities through indigenous gender constructs

      Apok, Charlene Aqpik; Topkok, Sean Asiqłuq; Rasmus, Stacy; Million, Dian; Demientieff, La Verne Xilegg (2021-05)
      Alaska Native Men's Voices, an exploratory project, begins to make visible experiences of what it means to identify as an Indigenous male. Indigenous sovereignty includes practice of Indigenous gender knowledge systems. Self- determination of health and wellness by honoring relationships necessitates the affirmation of Alaska Native Men's voices. The complexity and diversity of Indigenous masculinity cannot be homogenized or made into one definition; these are not the goals of the research. This project aimed to articulate how Alaska Native men self- identify, what meaningful intersections of lived experiences can be drawn, and how do these inform healthy gender relations for future generations. The approach in research methods, how the project was done, articulates values of Indigenous led research and scholarship. Findings from shared stories, 18 individual semi-structured interviews, describe notions of Indigenous masculinities rooted in cultural foundations, knowing one's self, having a sense of belonging, and honor relationships from individual, to family and community. Expansive understandings of holistic wellness include narrative of emotional and spiritual healing. Illustrations of ancestral connection and continuance are put forward by participants as expressions of love for future generations of Alaska Native men.
    • The all-night MFA feces incident (bark!) - a photographic novel

      Hindy, Gregory; Farmer, Daryl; Holt, Joseph; Heyne, Eric (2021-05)
      This is a hybrid work of writing, photography, memoir and novel, in which a dog, Pablo, narrates the life of his human, Gus. Gus, a barely fictional persona of the author, is an MFA student who cannot finish his meta-auto-fictional, dog-narrated thesis because he is a hapless perfectionist and now finds himself stressed out the night before a complete draft of his thesis is due, which also happens to be the night of the 2020 presidential election. Gus intends to stay up all night, but quickly falls asleep, so Pablo sits down and writes the 200 pages for him, a literally dog-narrated thesis. Beginning at 1:00 am and keeping track of time as he goes, Pablo is always moving ahead with the next thought in a fragmented, associative, and at times impulsive manner. Pablo thinks about Gus's struggle to write and the various "Incidents" in Gus's life, among other topics of interest to Gus (organized religion, climate change, irritable bowels, minimalism, falling in love, Trump etc.), while also going through Gus's emails, texts, books and photos. Pablo also finds plenty of time to cover some of his own interests (Pablo Ball, killing birds, etc.), philosophies, and opinions. This is part artistic manifesto, part comedy, part rant, part meta rant, and mostly a collage of "Incidents," voices and images that could be read in any order.
    • Analysis of the 2015 Sagavanirktok River flood: associated permafrost degradation using InSAR and change detection techniques

      McClernan, Mark Timothy; Meyer, Franz; Zwieback, Simon; Minter, Clifton (2020-08)
      In 2015, the Sagavanirktok River experienced a sequence of high, early-winter temperatures that lead to a buildup of aufeis. The buildup displaced the spring runoff causing widespread flooding. Flood waters inundated the surrounding tundra introducing heat into ground ice-baring soils. The Sagavanirktok River flood was caused by an extensive ice dam that developed the previous winter. The first flooding pulse started in April 2015, when an aufeis obstruction diverted river water to the surface. The obstruction caused flooding along 24 km of the Dalton Highway and its surroundings, necessitating a prolonged highway closure and emergency repairs. A second flooding pulse was caused by annual spring runoff in May 2015, which was driven by rapid snowmelt due to warm seasonal temperatures. The washed-out highway had to be closed again. Field investigations showed that thermal erosion of ice wedges in the tundra adjacent to the Dalton Highway caused local subsidence by several meters. However, the full environmental impact of the flood has not yet been quantified regionally or temporally. Thermokarst formation, can cause rapid ecological and environmental changes. Thawing of permafrost can lead to terrain instability as the melting of ground ice induces subsidence and loss of soil strength. The processes involved in permafrost degradation are complex, as is predicting terrain stability and the associated impacts to permafrost surrounding infrastructure. The immediate impact of the 2015 Sagavanirktok River flood is evident, which caused rapid terrain collapse in the vicinity of the Dalton Highway and the Trans-Alaska Pipeline near Deadhorse, North Slope Borough, Alaska. Thermal degradation of permafrost can be expressed as the change in the surfacemicrotopography over several years following a flood. Change detection, digital elevation model differencing, and InSAR were employed within the area of interest to understand the extent of the flood and deformation within inundated areas. To determine the likely impacted areas within the area of interest and expanse of the flood, an unsupervised change detection technique of high resolution TerraSAR-X and Sentinel-1 amplitude images was utilized. The topographic deformation analysis to determine the motion on the ground surface used a short baseline subset InSAR analysis of Sentinel-1 data during the summer season following the Sagavanirktok River flooding events. Additional deformation analysis was conducted with ALOS-2 data for annual comparison of the 2015 to 2019 summers. TanDEM-X digital elevation model differencing compared surface models generated from before and after the Sagavanirktok River flood. Elevation model differencing would identify the absolute change between the acquisition time of the surface models. A joint data analysis between deformation and differenced elevation models analyzed the contrast within inundated and flood-unaffected areas; thus, the changes and impact to the permafrost following the 2015 Sagavanirktok River flood. The Sagavanirktok River flood highlights the vulnerability of ice-rich permafrost to flooding. A change in the vicinity of the Sagavanirktok River Delta to the hydrological cycle led to widespread increases in terrain instability. Analysis of summer season deformation data suggested inundated permafrost areas showed lower seasonal deformation in years following the flood. Analysis of annual deformation shows permafrost subsidence intensified in inundated areas in the years following the flood. Digital elevation model differencing produced a statistically ambiguous result. This research illustrates the value of combining TerraSAR-X, TanDEM-X, Sentinel 1, and ALOS-2 microwave remote sensing missions for evaluating widespread surface changes in arctic environments. However, annual deformation data proved the most usable tool in observing the changing permafrost ecosystems around the Sagavanirktok River.
    • Anfechtung

      Lyew, Daniel Emerson; Johnson, Sara; Reilly, Terry; Carr, Richard; Farmer, Daryl (2021-05)
      This thesis is a collection of poetry that explores the relationships between time, memory, identity, freedom, and meaning within the context of a shifting and unsteady world. The collection is organized along a trajectory not unlike that of Dante's Divine Comedy, moving through inner and outer landscapes of uncertainty and anxiety before emerging in more ambiguous, subtle spaces. Allusion is used to suggest the continuity and fragmentariness of a tradition (similar to T. S. Eliot's "The Waste Land"), reformation and response to a tradition (as in Nets by Jen Bevin), and the chancy contingencies of personal experience. Formally, the poems use a wide variety of strategies and forms including erasure and non-traditional lineation to suggest various states of being ranging from the hypnagogic and nightmarish to the nostalgic and wistful, and ultimately to something like hope. The poems also range from highly confessional modes to more abstract, imagistic modes to similarly suggest motion and change.
    • Antibiotic resistance in a changing North: unearthing the effects of disturbance-induced permafrost thaw on the Alaskan soil resistome

      Haan, Tracie J.; Drown, Devin M.; Podlutsky, Andrej; Hueffer, Karsten; Burkhead, Jason (2021-08)
      The evolution of antibiotic resistance in pathogenic bacteria is a major threat at the forefront of public health today. By studying soils, one of the ancestral origins of antibiotic production and resistance, we can gain insight into how antibiotic resistance genes (ARGs) from the environment have contributed to the evolution and emergence of resistance in pathogens. These studies are particularly important in soils where polar amplification and human expansion has already impacted the frequency and intensity of soil disturbance events (e.g., wildfires, deglaciation, land-use). In Alaska these disturbances augment permafrost thaw shifting the biogeochemical properties of active layer soils that structure microbial community composition and hypothetically the resistome (i.e., summation of ARGs). Thus, the goal of this thesis was to assess how soil disturbance, and the subsequent shift in community composition, will affect the types, abundance, and mobility of ARGs that comprise the subarctic soil resistome. In the first chapter I cultured bacteria from a permafrost thaw gradient in Interior Alaska, tested the isolates for susceptibility to antibiotics, annotated their genomes for ARGs, and compared their resistance profiles to a global database of soil bacteria genomes. I found that phylogenic and ecological factors structured the resistome. Additionally, antibiotic resistance phenotypes and genotypes were widespread in the soil isolates suggesting resistance is an intrinsic component of bacterial evolution. In the second chapter, I used long read metagenomics to identify predominant ARGs, ARG host taxa, and the relationship between community composition and ARG abundance. From the long read data, I unearthed major trends in the types of ARGs at our study site and determined ARG abundance had a quadratic relationship with disturbance and negative relationship temporally by year highlighting the complex interplay soil conditions have in structuring the taxa that enrich ARGs in the community. To analyze how individual bacteria contribute to ARGs in the community, I generated metagenome assembled genomes (MAGs) using Hi-C proximity ligation. From the MAGs, I found a significant difference in ARGs per genome between phyla that emphasized how an enrichment of specific bacteria can affect the abundance of ARGs in subarctic soils. I also identified several plasmid-borne ARGs highlighting the potential for horizontal gene transfer. Overall, this thesis provides evidence that ARGs in permafrost-associated soil are structured by disturbance-induced community shifts. Thus, as climate change increases t the frequency of disturbance events that shift the microbial communities in active layer soils, One Health can be impacted by alterations to ARGs comprising the resistome.
    • Applicability of the Walder-Hallet frost fracture model to laboratory cyclic uni- and bi-direction freeze-thaw of limestone and sandstone

      Haas, Abram; Peterson, Rorik; Kim, Sunwoo; Zhang, Lei (2021-08)
      Due to changing climate conditions, new geographic areas are being impacted by diurnal and seasonal freezing and thawing conditions. Many geologic materials in far north latitude areas, that had not undergone significant freeze and thaw previously, are now expected to experience those conditions more often. The bedrock in these northern regions is often used as the foundation for many buildings and other infrastructure, and so it is extremely important to understand the integrity of this material with the changing conditions. Walder and Hallet created a theoretical model to analyze the temperature of fine cracks within a rock when subjected to freezing conditions, and the growth of fine cracks due to thermally-induced water migration followed by freezing. More recently, Dr. Murton conducted multiple cyclic unidirectional and bidirectional freeze-thaw experiments in the laboratory that simulated active layer rocks both with and without permafrost below. These experiments measured temperature and pore pressure of the rock, and monitored the formation and growth of macroscopic (i.e. observable) cracks. Using Walder and Hallet's model as a starting point, I have created a numerical model to analyze the cyclic fluctuating temperature conditions used by Murton in his experimental work, but is not accounted for in the original Walder and Hallet model. I then compared his laboratory results with the numerical model predictions of temperature and location of observable crack growth. This required adjusting some model parameters used by Walder and Hallet to correspond with the experimental conditions and geological materials used. I found that the model predicts the correct location of maximum cracking, and the time of observable crack growth, for the unidirectional experiments. However, it predicted nearly the opposite of the laboratory results for the bidirectional experiments. To obtain these numerical results, I had to adjust parameters that attempt to describe the flow resistance within a fine-grained freezing rock material; a difficult and little understood phenomenon. Future work should focus on improving some of the original model assumptions that do not apply to most experimental situations including those of Murton. These include the angle of cracks, and the potential interaction between adjacent cracks. While the results of this numerical model did not predict all the observed results of Murton's experiments, it has shown what portions of the numerical model appear to work correctly, and what assumptions from the original theoretical model by Walder and Hallet need to be adjusted and improved.
    • Applications of stable isotope analysis to advancing the understanding of brown bear dietary ecology

      Rogers, Matthew C.; Barnes, Brian; Welker, Jeffrey; Brinkman, Todd; Gustine, David; Hilderbrand, Grant (2021-08)
      Dietary ecology is one of the most important drivers of brown bear fitness at the individual and population levels. However, researchers do not have an in-depth understanding of the trophic niche breadth, diet composition, and seasonal diet variation for most Alaskan populations. I set out to better understand multiple facets of brown bear dietary ecology using stable isotope analysis (¹³C & ¹⁵N) as the primary tool to infer brown bear diet and gain insights into their trophic niche, dietary seasonality, dietary generalism and specialism, and isotopic trophic discrimination factors. I determined that using sectioned hair samples is the best practice for determining the isotopic trophic niche of brown bears. Additionally, I determined amino acid trophic discrimination factors for brown bears and explored the ability to separate salmon species in bear diets. I also used stable isotope mixing models with sectioned hair samples to infer seasonal dietary patterns of individual bears in five distinct Alaskan ecosystems. Approximately one-quarter of bears relied solely on vegetation over multiple years despite access to other sources of nutrition; these bears could be considered specialists. Other bears, approximately half, switched diets seasonally but had the same pattern of resource use year over year, a foraging class that I termed persistent seasonal generalism. Approximately one-quarter of bears did not have a persistent dietary pattern across years and could be considered true generalists. Most bears appear to have preferred dietary patterns that are persistent through time, which may be indicative of foraging inertia; maintaining foraging patterns even when faced with changing resource availability due to natural fluctuations, disturbance, or climate change. The sum of this work advances our understanding of brown bear dietary ecology from the individual seasonal level to population level degrees of generalism and specialism, and the methods developed can be applied to many species for which dietary ecology information is difficult to obtain.
    • Assessing adverse effects of mercury in two pinniped species

      Lian, Marianne; O'Hara, Todd M.; Rea, Lorrie D.; Kuhn, Thomas B.; Van Wijngaarden, Edwin (2020-08)
      This dissertation studies measures of adverse effects in free-ranging pinnipeds associated with relatively high total mercury ([THg]) or monomethylmercury ([MeHg+]) concentrations, relatively low total selenium ([TSe]) concentrations and/or low TSe:THg molar ratios. Both the Steller sea lion (SSL, Eumetopias jubatus) and Pacific harbor seal (HS, Phoca vitulina richardii) inhabit coasts of the North Pacific, and are considered important sentinel species for One Health (environmental, animal and human health). Relatively high [THg] is reported for some animals in both species, causing concern for adverse effects especially in the developing fetus. Maternal piscivorous diet can expose the fetus to MeHg⁺ at a vulnerable developmental stage, with potential for adverse effects on several organ systems. This dissertation focused on two of these: nervous system development and function and oxidant/antioxidant homeostasis. In Chapter 2 I outlined capture and field anesthesia of free-ranging SSL. I found faster induction times for sevoflurane over isoflurane, with a significant interaction for anesthetist. Difference among the two agents is most likely attributed to the different chemical properties for these gases (blood solubility), whereas personal experience/comfort level most likely explains the differences between the human operators. Severe hypothermia was also documented, associated with the time of year, sex and duration of anesthetic event. There was an overall low mortality rate, and the protocols were effective for relatively safe field anesthesia of a large mammal. Chapter 3 assessed oxidant/antioxidant status and associations with [THg], [MeHg⁺], [TSe] and TSe:THg molar ratio in anesthetized free-ranging SSL pups. The anesthesia protocols described in Chapter 2 were used as a physiological stressor for measuring oxidative stress in SSL. Pinnipeds as diving mammals are naturally adapted with high antioxidant activity to survive long breath-holds during foraging. However, the relatively high [THg] found in some SSL cause concern for sequestration of Se due to its high binding affinity to Hg, and subsequently decreased antioxidant capacity (Se-dependent glutathione peroxidase (GPx)). I found a significant negative relationship between lipid peroxidation and [TSe], suggesting the potential for decreased antioxidant protection from Se. There were also significant associations between increased GPx activity and lipid peroxidation, possibly protecting pups with relatively high [THg] and low TSe:THg molar ratios. In Chapter 4 I repeatedly evaluated live-stranded HS pups admitted to The Marine Mammal Center, using weekly clinical and behavior assessments, which were analyzed for associations with [THg]. There was a significant association between [THg] in hair and/or blood and decreased response to tactile stimulation, less movement and longer stays in rehabilitation. These findings will help us better assess similar [THg] in hair and blood of SSL in Alaska that we currently study as well as other pinnipeds. In summary, this dissertation confirms the potential for adverse effects in two free-ranging species of pinnipeds exposed to MeHg⁺ in utero.
    • Assessing the long-term growth response and age estimation precision for Arctic whitefishes in a rapidly changing nearshore environment

      Gatt, Kyle P.; Sutton, Trent M.; von Biela, Vanessa R.; McPhee, Megan V. (2021-05)
      Accurate monitoring of population-level health and productivity is essential for assessing the status and availability of subsistence harvested species at the forefront of climate change. This study used otolith biochronology to assess the long-term growth response of Arctic Cisco Coregonus autumnalis during a period of rapid environmental change in the Beaufort Sea region and to identify drivers of growth. A biochronology spanning 22 years (1996-2018) revealed significant interannual variation, with faster growth rates in years with warmer (R² = 0.31) and more saline (R² = 0.47) waters during the ice-free summer feeding period (July-September). These results suggested that warming may benefit Arctic Cisco. This study also compared age estimates made using fin rays, scales, and otoliths of four subsistence whitefishes (Arctic Cisco, Least Cisco Coregonus sardinella, Broad Whitefish Coregonus nasus, and Humpback Whitefish Coregonus pidschian) from the Beaufort Sea to compare the aging precision of non-lethal structures (fin rays and scales) to otoliths. Fin rays and scales provided similar age estimates as otoliths until the age of sexual maturity and underestimated otolith age for mature individuals. Scales underestimated age more often and were more difficult to which to assign age than the other two structures. Among Arctic Cisco in Alaska, fin rays and scales provided similar age estimates as otoliths for all age and size classes examined because most individuals in the study area were immature fish. These results suggested that dorsal fin rays may be used to estimate age in Least Cisco <300 mm, Broad Whitefish <450 mm, and Humpback Whitefish <350 mm, and that otoliths should remain the primary aging structure for the largest whitefishes. Overall, this research complements existing monitoring by providing evidence of an Arctic subsistence species that may benefit in part from warming and highlights non-lethal alternatives for monitoring the age structure of juvenile whitefishes.
    • Atmospheric modeling of natural hazards

      Hirtl, Marcus; Stuefer, Martin; Webley, Peter; Simpson, William; Grell, Georg (2021-05)
      Airborne hazards either in gaseous form or particulate matter can originate from a variety of sources. The most common natural airborne hazards are ash and SO₂ released during volcanic eruptions, smoke emitted caused by wildfires and dust storms. Once released into the atmosphere they can have a significant impact on different parts of the environment e.g. air quality, soil and water, as well as air traffic and ground transportation networks. This latter field is an important aspect of everyday life that is affected during hazardous events. Aviation is one of the most critical ways of transport in this century. Even short interruptions in flight schedules can lead to major economic damages. Volcanic eruptions comprise one of the most important airborne hazards to aviation. These are considered rare as compared to severe weather, but with an extremely high impact. This dissertation focusses on dispersion modeling tools and how they can support emergency response during different phases of volcanic eruption events. The impact of the volcanic ash cloud on the prediction of meteorological parameters and furthermore the dispersion of the ash is demonstrated by applying the Weather Research Forecasting (WRF) model with on-line integrated chemical transport (WRF-Chem) to simulate the 2010 Eyjafjallajökull eruption in Iceland. Comprehensive observational data sets have been collected to evaluate the model and to show the added value of integrating direct-feedback processes into the simulations. The case of the Eyjafjallajökull eruption showed the necessity to further develop the volcanic emission preprocessor of WRF-Chem which has been extended for flexible and complex ash and SO₂ source terms. Furthermore, the thesis describes how scientists could support operational centers to mitigate hazards during a large volcanic eruption event. The author of the dissertation coordinated a large exercise including experts across all Europe within a project funded by the European Union. The exercise aimed to develop and test new tools, models, and data to support real-time decision making in aviation flight planning during a volcanic crisis event. New state-of-the-art modeling applications were integrated into a flight planning software during a fictitious eruption of the Etna volcano in Italy with contributions from scientists, the military and the aviation community.
    • Beyond trending: using risking connection as a framework for moving agency culture toward trauma-informed care

      Healey, Michael J.; Renes, Susan L.; Strange, Anthony; Baker, Courtney; Anahita, Sine (2020-08)
      The prevalence and pervasive impact of adverse childhood experiences (ACEs), and more broadly, trauma, are well supported in the extant literature. Despite this evidence, there remains a significant dearth of formal training and educational programs that prepare staff who work with trauma survivors within complex behavioral health systems. Trauma-informed care (TIC) has moved beyond a trend in the mental health field and is gaining momentum as a leading philosophical paradigm that is being infused as an operational framework for agencies that work with survivors. Risking Connection (RC) is a curriculum-based training program that works with agencies interested in becoming trauma-informed. The current study examined the impact of RC on trainee outcomes for knowledge gain, attitude change, and vicarious trauma (VT) on 119 participants who all work for a therapeutic group home system being operated by a provincial government in Atlantic Canada. The findings in this study suggest that RC is effective in improving knowledge gain and attitude change in a favorable direction toward TIC. The study also supported previous findings associated with the improvement of VT.
    • Blood falls, Taylor Glacier, Antarctica: subglacially-sourced outflow at the surface of a cold polar glacier as recorded by time-lapse photography, seismic data, and historical observations

      Carr, Chris G.; Pettit, Erin; Carmichael, Joshua; Truffer, Martin; Tape, Carl (2021-05)
      Blood Falls forms when iron-rich, hypersaline, subglacially-sourced brine flows from a crack in the surface of Taylor Glacier, Antarctica. If air temperatures are low enough, the brine freezes to form a fan-shaped icing deposit. In chapter two, historical observations (including photos, oral histories, written descriptions, and field sketches) are evaluated using a confidence assessment framework to compile a history of brine icing deposit presence or absence during summer field seasons between 1903-1904 and 1993-1994. Additionally, an alternative explanation for a small, localized advance of a portion of the terminus is proposed: rather than temperature-driven ice viscosity changes, rising lake level drove temporary, localized basal sliding which induced advance, thinning, and collapse of a part of the terminus previously grounded on a proglacial moraine. In chapter three, time-lapse imagery is used to document a 2014 wintertime brine release that occurred in the absence of surface melt. This suggests that meltwater-driven fracture propagation of surface crevasses downward into the glacier was not a likely factor in this brine release event, as has been previously proposed. Further, there is no evidence for an increase in Rayleigh-wave activity prior to or during the brine release that would be characteristic of shallow seismic sources. Together, this suggests that sufficient pressure is built in the subglacial system to trigger basal crevassing and fracture propagation upward to allow brine release at the surface. In chapter four, two different seismic detectors that use ratios of short-term to long-term seismic energy variance to identify seismic events are compared. The detectors use different statistical distributions to determine what constitutes a large enough ratio to trigger an event detection. Differences between what the two detectors identify as events rather than background noise are interpreted as environmental microseismicity with a distinct diurnal and seasonal occurrence. Minimum detectable event sizes over 3-day time windows are compared. Together, these studies provide context for the history of brine release events, wintertime brine release characteristics, and descriptions of the local seismic environment at Taylor Glacier.
    • Born to burn: characterizing fuel loads, flammability and plant traits across spatio-temporal gradients of black spruce dominated communities

      Grzesik, Emilia J.; Ruess, Roger; Hollingsworth, Teresa; Turetsky, Merritt (2020-12)
      The flammability of black spruce forests is influenced by the fuel loadings and quality of fuels within a site, whereas the ability of a site to self-replace after fire, and thus forest resiliency, depends on the fire-ecological trait attributes of the plant community. Black spruce plant communities have been undergoing self-replacement succession from low to moderate severity fires for thousands of years, however, recent intensification of interior Alaska's fire regime is leading to shifts in post-fire successional trajectories, resulting in many ecological implications. This study focuses on understanding the variation in black spruce forest flammability, based on fuel load quantity and quality, and fire-ecological plant traits in 28 black spruce dominated sites ranging across age and moisture gradients in interior Alaska. I quantified tree canopy, understory and below-ground fuel loads, developed models to predict fuel loads and then utilized my measurements of above-ground fuel load quantity and quality to calculate a site-level flammability index. Based on my analyses, significantly greater flammability indices, and thus burning potential, occur in sites greater than 34 years in age, at elevations greater than 302 m and with dry site moisture, which are representative of dry, nonacidic upland black spruce and dry, acidic upland black spruce-lichen forest ecosystems. Furthermore, although fire-ecological plant trait attributes of Hylocomium splendens and Vaccinium uliginosum vary with age and moisture gradients, the amount of intra-specific trait variation within a site could not be explained by stand age or moisture and thus forest resiliency is also likely independent of age and moisture gradients. Further research is necessary to explore both abiotic and biotic explanatory variables related to intra-specific plant trait variation to better understand variation in black spruce forest resiliency on the landscape. The results from this study can assist fire managers in the prediction of black spruce forest burning potential and its vulnerability to ecosystem shift post-fire.
    • Bridging expert knowledge and fisheries data to inform assessment and management of rockfishes in the Gulf of Alaska

      Gordon, Jesse; Beaudrau, Anne; Carothers, Courtney; Williams, Benjamin (2021-08)
      Over the past few decades, nearshore rockfishes (Sebastes spp.) have experienced increased pressure from multiple fisheries throughout the Gulf of Alaska. The unique life history traits of rockfishes pose a host of challenges that make them difficult to monitor and vulnerable to overfishing. Rockfishes are economically and culturally important to coastal communities in the Gulf of Alaska. Therefore, the inclusion of fishers' knowledge in rockfish assessment and management will help to address biological goals and meet the needs of a growing fishery. This thesis examines the recent history and current management issues in nearshore rockfish fisheries in the Gulf of Alaska through triangulation of expert knowledge, fishery data, and biological surveys. We conducted semi-structured interviews with 43 fishers and agency staff who have long-term knowledge of and experience in rockfish fisheries within the Sitka and Kodiak areas. Chapter One presents a synthesis of changes in commercial and recreational rockfish fisheries since the 1970s, based on datasets from the Alaska Department of Fish and Game (ADF&G) and expert knowledge from interviews. Harvest data indicated both increases and decreases in nearshore fishing effort and harvest patterns, depending on the fishery sector, region, and rockfish species. Fishers and agency staff offered a longer-term and contextual understanding of changes in rockfish abundance. Most experts observed an overall decline in pelagic rockfishes near Sitka, AK and more variable patterns of abundance near Kodiak, AK. While many experts were hopeful about future sustainability of rockfish fisheries, others expressed concern about increases in localized fishing pressure, growth of charter fishing, barriers to access in some fisheries, and declines in rockfish biomass. Chapter Two identified institutional pathways and gaps in public engagement with rockfish fisheries management in Alaska. Fishers and agency staff highlighted the value of formal and informal institutions for effective engagement and emphasized the importance of relationship building and trust between fishers and agency staff. Fishers demonstrated stewardship over their fisheries through participation in local to state management processes, establishing norms of sustainability within fishing associations, and by taking personal actions to promote fishery conservation. Experts identified institutional gaps which included transparency issues regarding regulations, underrepresentation of recreational and subsistence harvesters in the Board of Fisheries public process, and communication barriers between the sport and commercial divisions of ADF&G. Our findings highlight the challenges of bringing together disparate data sources and the benefits of including multiple ways of knowing to produce a more complete understanding of dynamic fishery systems.
    • Bristol Bay dual permit operations, vessel heterogeneity, and the migration of Alaskan permit holders

      Gho, Marcus J.; Criddle, Keith; Adkison, Milo; Adkison, Milo; Twomley, Bruce; Brown, Benjamin (2020-08)
      This dissertation examines three aspects of Alaska's Limited Entry program. Chapter 1 explores the outcome of dual-permit regulations. The Alaska Board of Fisheries passed regulations allowing for dual permit operations in the Bristol Bay Pacific salmon drift gillnet fishery starting in 2004. These regulations allow two permit holders to fish from a single vessel with additional gear. Policymakers anticipated that the dual permit regulations would encourage young fishermen to enter the fishery and reduce the number of limited entry permits transferred from local fishermen to nonlocal fishermen and nonresidents. Statistical analyses reported in Chapter 1 indicate that the dual-permit program successfully offset part of the adverse influence of increases in the market value of permits on the number of new entrants and that implementation of dual-permit regulations was followed by a reduction in the median age of new entrants, particularly among nonresidents. However, the implementation of dual-permit regulation failed to staunch the outflow of limited entry permits. Chapter 2 examines the persistence of heterogeneity in the size of fishing vessels active in the Bristol Bay salmon drift gillnet fishery. When entry was limited, the commercial fishing fleet included a mix of vessels up to the long-established 32-foot maximum length. The race for fish that so often arises under license limitation favors the adoption of vessel and gear configurations that maximize catch-perday and could be anticipated to lead to increased homogeneity in fleet composition. Yet, statistical analyses indicate that even after over four decades, the composition of this fleet remains heterogeneous in vessel size and vessel value. Multivariate analysis of time series observations of vessel values indicates that vessels captained by permit holders who were given their permit are less capitalized than vessels captained by permit holders who purchased their permit. Likewise, vessels operated by local resident permit holders are less capitalized than vessels owned by nonlocal Alaskan or nonresident permit holders. In addition, vessels operated by older permit holders are less capitalized than vessels operated by younger permit holders. Chapter 3 examines the factors that influence the migration of permit holders. Since limitation, there have been concerns that ever more of the permits issued to individuals local to Alaska's fisheries would come to be held by individuals who were not local to the fisheries. The count of permit holders local to a fishery can change because of transfers, administrative cancellations, or because permit holders migrate either to or from fisheries where the permit is used. Chapter 3 considers possible factors that predict permit migration to or from different residency classes. Included in our analysis was a look at season length, fleet participation rates, permit transfers, the size of the fleet, gear type, wages of construction workers to serve as a proxy for substitute employment, and the local unemployment rate. Statistical analyses indicate that fisheries with longer seasons show slightly elevated migration from local to nonresident status of permit holders. Permit latency and permit holder migration have a negative relationship among the significant variables. Transfers serve as a substitute for permit migrations and provide the largest influence on permit migrations. For every resident type of migration, as the transfer rate increases, fewer permit holders migrate. The total number of permits within the fishery also affects the migration of permit holders, albeit only minimally. The second-largest influence on permit migration is gear type. Migrations to local setnet permit holders had a smaller magnitude of change than migrations from permit holders across most categories. Generally speaking, migration tends to move towards a nonresident status of permit holders. Wages of construction workers were only significant at the 5% level for transfers from locals to nonresidents and from nonresidents to locals, but both variables were positive. As the local unemployment rate increases, the rate of locals emigrating outside of Alaska increased.
    • Broad whitefish (Coregonus nasus) ecology and habitat use in Arctic Alaska: spawning habitat suitability, isotopic niches, life-history variations, and climate change risks to subsistence fisheries

      Leppi, Jason C.; Wipfli, Mark S.; Rinella, Daniel J.; Seitz, Andrew C.; Falke, Jeffrey A. (2021-08)
      Broad Whitefish (Coregonus nasus) is a critically important subsistence species for Alaska's Indigenous communities, yet little is known about the basic ecology of this species at the individual level. Understanding habitat use by Broad Whitefish is challenging due to their mobility and our limited ability to track fish throughout their lives as they move among a suite of habitats that are spatially dispersed, change over time, and are often temporary. The Arctic is undergoing major landscape and ecosystem transformation from climate change and oil and gas development, which may threaten Arctic ecosystems used by Broad Whitefish. This dissertation presents new information on the ecology of Broad Whitefish captured in the Colville River, Alaska. In Chapter 1, an intrinsic potential (IP) model for Broad Whitefish was used to estimate the potential of streams across the watershed to provide spawning habitat. Results were compared with movement patterns of radio-tagged prespawn Broad Whitefish. In Chapter 2, ecological niches utilized by Broad Whitefish were investigated via stable isotope analyses of muscle and liver tissue and otoliths from mature fish. In Chapter 3, strontium isotope (⁸⁷Sr/⁸⁶Sr, ⁸⁸Sr) otolith chronologies across individuals' lives were used to quantify life-history attributes and reconstruct migration patterns of fish. Finally, in Chapter 4, the current understanding of ongoing and future changes to the habitat, productivity, and behavior of Broad Whitefish were summarized to assess risks facing Arctic freshwater ecosystems and fishes more broadly. IP model results showed the majority of habitat with high IP (≥ 0.6) was located within the braided sections of the main channel, which encompassed > 1,548 km, and starting in mid-July, prespawn fish used habitats in the middle and lower watershed. Stable isotope analysis revealed a range of [delt]¹³C (-31.8- -21.9‰) and [delta]¹⁵N (6.6- 13.1‰) across tissue types and among individuals. Cluster analysis of muscle tissue δ¹³Cˈ, δ¹⁵N, δ¹⁸O, and δD indicated that Broad Whitefish occupied four different foraging niches that relied on marine-and land-based (i.e., freshwater and terrestrial) food sources to varying degrees across the summer period. Strontium isotopes revealed six main life histories, including three anadromous types (59%), one semi-anadromous type (28%), and two nonanadromous types (13%), suggesting greater complexity in life-history types than previously documented. Climate change is expected to continue to alter Arctic hydrology and, therefore, suitability, connectivity, and availability of habitats critical for Broad Whitefish population persistence. Warming and lengthening of the growing season will likely increase fish growth rates; however, the exceedance of threshold stream temperatures will likely increase physiological stress and alter life histories, which is likely to have mixed effects on Arctic subsistence fishes and fisheries. This information on Broad Whitefish spawning intrinsic potential, foraging niches, and life histories provides crucial knowledge to understand critical habitats used across time and space, which will help managers and conservation planners better understand the risks of anthropogenic impacts, such as climate change and oil and gas development, and help conserve this vital subsistence resource.